Precision load-positioning device for cranes



June 26, 1956 A. B. BOGLE 2,752,120

PRECISION LOAD-POSITIONING DEVICE FOR CRANES Filed Jan. 15, 1954 2 Sheets-Sheet'l 34- m #0 /38 3g 3 a2 IN V EN TOR.

By flarey B. Boy/e June 26, 1956 A. B. BOGLE 2,752,120

PRECISION LOAD-POSITIONING DEVICE FOR CRANES Filed Jan. 13, 1954 2 Sheets-Sheet 2 INVEN TOR.

United States Patent PRECISION LDAD-POSTTIONING DEVICE FOR CRANES Aubrey B. Bogie, Highland Fark, Mich.

Application January 13, 1954, Serial No. 463,709

8 Claims. (Cl. 254-168) This invention relates to cranes and, in particuar, to load-positioning mechanisms for cranes.

One object of this invention is to provide a crane with a precision load-positioning device whereby work may be picked up from or deposited upon a given location with a higher degree of accuracy than has hitherto been possible.

Another object is to provide a crane of the foregoing character wherein the load is positioned precisely by mounting the cable equalizer pulley upon an adjustable support which can be moved upward or downward by small increments in order to elfect a fine adjustment of the load relatively to the location where it is to be picked up or deposited.

Another object is to provide a crane as set forth in the object immediately preceding wherein the cable equalizer pulley support is mounted upon screw shafts which are adjusted upward or downward by means of rotary nuts driven by an operating motor under the control of the operator.

Another object is to provide a crane of the foregoing character wherein the precision adjustment of the equalizer mechanism is adapted to cranes wherein the load is supported by four or six or a greater number of cable branches.

Other objects and advantages of the invention will become apparent during the course of the following description of the accompanying drawings, wherein:

Figure 1 is a top plan view of an overhead traveling crane having a precision load-positioning means, according to one form of the invention, as applied to a fourbranch cable system;

Figure 2 is a side elevation, partly in vertical section, taken along the line 2-2 in Figure 1, additionally showing the longitudinal carriage and one of the longitudinal rails;

Figure 3 is a fragmentary vertical section taken along the line 3-3 in Figure 2, at right angles to the view shown in Figure 2;

Figure 4 is an enlarged side elevation, partly in vertical section, of the precision load-positioning device shown in the upper central portion of Figure 2;

Figure 5 is a vertical section taken along the line 55 in Figure 4;

Figure 6 is a horizontal section taken along the line 6-6 in Figure 5; and

Figure 7 is a fragmentary side elevation, partly in vertical section, of a modification of the invention as applied to a six-branch cable system.

Hitherto, Where cranes, such as, for example, overhead traveling cranes, have been provided for raising and lowering loads and transferring them from place to place, it has been diflicult to accurately position the loadcarrying hook or other load carrier relatively to the location at which the load is to be picked up or deposited, since the operation of the motor which rotates the rope drums or winches moves the hook or other load carrier upward or downward in relatively large increments which ice are not conducive to precise operation. The present invention provides a fine adjustment for. such cranes consisting of a vertically-movable support for the cable equalizer pulley of the crane, together with mechanism driven by an auxiliary motor by which this support may be moved upward or downward by small increments. The invention is adaptable either to a four-branch cable system (Figures 1 to 6 inclusive), to a six-branch cable system (Figure 7) or to a cable system with a greater number of branches. The invention may likewise be applied to a cable system of eight or more branches by an obvious extension and adaptation of the mechanism disclosed herein.

Referring to the drawings in detail, Figures 1 to 6 inclusive show a crane, particularly an overhead traveling crane, designated 10, for picking up or depositing a load at one location and transferring it to another location. The invention, however, is not confined to use with traveling cranes, but may also be applied to stationary cranes. The crane 10 is provided with a lower carriage or longitudinal bridge, generally designated 12, by which it travels longitudinally from place to place, and is also provided with an upper or transverse carriage or trolley 14 by which the load carrier is moved transversely back and forth relatively to its longitudinal path of travel.

The lower or longitudinal carriage or bridge 12 consists of a frame or chasis 16 having spaced longitudinal structural members 18 of any suitable form, such as the I-beams shown in Figure 2 interconnected by spaced transverse structural members 20 likewise of I-beam or other suitable form. The frame or chassis 16 thus is a rectangular structure, wherein axles 22 are journalled in the forward and rearward ends of the longitudinal members 18, the axles 22 supporting flanged wheels 24 engaging transversely-spaced parallel longitudinal rails 26. The rails 26 are supported in an overhead position by a conventional supporting structure of any suitable character, such supporting structures being well-known to engineers skilled in the overhead traveling crane art.

Mounted transversely upon the frame 16 of the lower or longitudinal carriage 12 and resting upon the transverse structural members 20 are longitudinally-spaced transverse rails 28. The rails 28 are engaged by flanged wheels 30 mounted upon axles 32 and 33 journaled in brackets 34 secured to the four corners of the rectangular base 36 of the upper transverse carriage 14. The base 36 is made up of structural members (not shown) arranged in a rectangular structure upon which a supporting plate or base plate 38 is mounted. Bolted or otherwise secured to the base 36 on opposite sides thereof are a bearing bracket 40 and a housing 42 of a reduction gearset 44. Iournalled in the bracket 40 and housing 42 are the opposite ends of a drum or winch shaft 46. Secured to the drum shaft 46 within the housing 42 is a gear 48 which meshes with a smaller idler gear 50 mounted upon an idler shaft 52, the opposite ends of which are likewise journaled in the housing 42. Meshing with the ilder gear 56 is a drive pinion 54 mounted upon a drive shaft 56 likewise journall'ed in the housing 42 and drivingly connected to the shaft 58 of a main driving motor 60 (Figure 1). The motor shaft 58 is provided with a brake drum 62 engaged by a band brake 64 mounted upon a support 66 and actuated by a solenoid 68, thereby providing a magnetic brake, generally designated 76, connected to the motor circuit and operated to halt the rotation of the motor shaft 58 instantly upon de-energization of the motor 60.

Secured as at 72 and 74 to the winding drum 76 mounted upon the drum shaft 46 are the opposite ends of a hoisting cable, generally designated 78,,having four branches 8% 82, 84 and 86 respectively. The cable branches 80 and 82 pass downward from their anchorages 72 and 74 respectively on the drum 76 to a lower block 87, where they pass beneath coaxial pulleys 88 and 90 loosely and rotatably mounted upon the opposite ends of a pulley shaft 92 having an enlarged central portion 94 drilled as at 96 to receive the shank 98 of a load holder or hook 100. The upper end of the shank 98 is threaded to receive a retaining nut 102. The pulleys 88 and 90 are held in position by washers 104 and retaining pins 106, such as cotter pins.

After the cable 78 passes under the pulleys 88 and 90, its branches 84 and 86 pass upward and over a precision load-positioning device generally designated 107, which includes an equalizer pulley 108 loosely and rotatably mounted upon a shaft 110. The shaft 110 is supported in vertically-notched brackets 109 mounted upon the base plate38 on opposite sides of the equalizer pulley 108. The opposite ends of the equalizer pulley shaft 110 are drilled as at 111 to receive the upper ends of spaced vertically-disposed screw shafts 112 (Figure pinned or otherwise secured thereto as at 113. The screw shafts 112 pass downward through gear nut housings 114 having caps or covers 116 bolted to the upper sides thereof (Figure 5). The gear nut housings 114 are bolted as at 118 to the base plate 38 and are cup-shaped to receive annular ball thrust bearings 120.

Rotatably mounted upon the thrust bearings 120 within the geared nut housings 114 are gear nuts 122, the hubs of which are internally-threaded as at 124 to threadedly engage the screw shafts 112. The gear nuts 122 have worm wheel peripheries 126 which mesh with worms 128 keyed or otherwise drivingly secured to the opposite ends of worm shafts 130 journalled at spaced locations in the lateral extensions 132 of the gear nut housings 114 (Figure 6). The adjacent ends of the worm shaft 130 pass through suitable holes 134 in the notched brackets 109 and are drivingly connected to one another by a suitable shaft coupling 136. The outer end of one of the shafts 130 becomes the output shaft of a reduction gearset 138, the input shaft 140 of which is the motor shaft of the precision adjusting motor 142.

In order to propel the upper or transverse carriage 14 to and fro along the transverse rails 28, the pair of wheels 30 mounted on the axle 33 (Figure 1) are keyed or otherwise drivingly secured thereto. The axle 33 passes through and becomes the output shaft of a reduction gearset 142, the input shaft 144 of which is the motor shaft of a motor 146 mounted upon a platform or shelf 148 secured to and projecting laterally from the base 36 of the upper carriage 14. The motors 60, 142 and 146 are preferably reversible electric motors.

In the operation of the form of the invention shown in Figures 1 to 6 inclusive, the lower or longitudinal carriage 12 is propelled to and fro along the longitudinal tracks 26 by a motor and reduction gearset (not shown) drivingly connected to one of the axles 22 of the wheels 24 until it arrives over the location at which the load is to be picked up. Either simultaneously or subsequently, the upper or transverse carriage 14 is moved back and forth along the transverse rails 28 by operating the transverse propelling motor 146 to rotate the axle 33 (Figure 1) until the load holder 100 arrives directly over the load. The driving motor 60 is then operated to rotate the cable drum 76 through the reduction gearset 44 in order to unwind the cable 78 therefrom and lower the load holder or book 100 to the approximate level of the load.

The auxiliary motor 142 is then operated in one direction or the other, depending upon whether the hook or other. load holder 100 is to be raised or lowered precisely, to rotate the gear nuts 122 in one direction or the other, thereby causing the screw shafts 112 and the equalizer pulley axle 110 to rise or fall precisely. This in turn provides a fine adjustment which moves the equalizer pulley 108 upward or downward by small invice, generally designated 151, is somewhat different.

crements, so as to correspondingly raise or lower the hook or other load holder by fine increments in a precise manner. In this way, the load holder 100 is brought to the exact level of the load without depending upon the haphazard operation and repeated reversal of the main driving motor 60. When the load is thus attached to the load holder 100, the crane 10 is operated in the usual manner described above to transfer the load to the desired new location, after which it is raised or lowered by large increments by the use of the main driving motor 60, reduction gearset 44 and cable drum 76, and adjusted by fine increments through the auxiliary motor 142, reduction gearset 138, gear nuts 122 and screw shafts 112 in the manner described above.

The modification shown in Figure 7 illustrates the application of the invention to a crane having a greater number of branches to the cable or rope than the fourbranch installation shown in Figures 1 to 6 inclusive.

The installation, generally designated 150, in Figure 7 is generally similar in construction to that of Figures 1 to 6 inclusive and similar parts accordingly bear similar reference numerals, but the precision load-positioning de- In the Figure 7 modification, however, the cable branches 84 and 86, instead of passing over and meeting above a single equalizer pulley 108 as in Figures 1 to 6 inclusive, pass over a pair of laterally-spaced coaxial equalizer pulleys 152 and 154 and continue downward in two additional branches 156 and 158, and finally pass under an additional idler pulley 160 mounted on an axle 162 supported by spaced parallel ears 164 (one only being shown) secured to and rising from the enlarged central portion 94 of the lower block 87 on opposite sides of the hole 06 for the hook shank 98.

The remainder of the construction shown in Figure 7 is the same as that shown in Figure 1, and the mode of operation is also substantially the same. In Figure 7, however, the precision load positioning device 151 raises and lowers both equalizer pulleys 152 and 154 simultaneously by raising and lowering their common supporting shaft by moving the screw shaft 112 upward or downward in response to the rotation of the gear nuts 122 within the gear nut housings 114. This action provides a fine adjustment for raising and lowering the load holder 100 by small increments after the rough adjustment has been made by rotating the drum 76.

What I claim is: I

1. In a crane including a supporting structure carrying a rotatable cable winding drum and a rotatable equalizer pulley together with a hoisting cable trained around said drum and around the pulleys of a load-holding block suspended therefrom and also around said equalizer pulley, a precision load-positioning device comprising an equalizer pulley support movably mounted upon said supporting structure for travel relatively thereto and having said equalizer pulley rotatably mounted thereon, and power-driven mechanism operatively engaging said support for moving said support and said equalizer pulley relatively to said supporting structure toward and away from said load-holding block.

2. In a crane including a supporting structure carry ing a rotatable cable winding drum and a rotatable equalizer pulley together with a hoisting cable trained around said drum and around the pulleys of a load-holding block suspended therefrom and alsoa-round said equalizer pulley, a precision load-positioning device comprising an equalizer pulley support movably mounted upon said supporting structure for travel relatively thereto and having said equalizer pulley rotatably mounted thereon, and power-driven mechanism operatively engaging said support on opposite sides of said equalizer pulley for moving said support and said equalizer pulley relatively to said supporting structure toward and away from said loadholding block.

3.11; a crane including a supporting structure carrying a rotatable cable winding drum and a rotatable equalizer pulley together with a hoisting cable trained around said drum and around the pulleys of a load-holding block suspended therefrom and also around said equalizer pulley, a precision load-positioning device comprising an equalizer pulley support movably mounted upon said supporting structure for travel relatively thereto and having said equalizer pulley rotatably mounted thereon, powerdriven mechanism operatively engaging said support for moving said support and said equalizer pulley relatively to said supporting structure toward and away from said load-holding block, and an adjusting motor drivingly connected to said mechanism.

4. In a crane including a supporting structure carrying a rotatable cable winding drum and a rotatable equalizer pulley together with a hoisting cable trained around said drum and around the pulleys of a load-holding block suspended therefrom and also around said equalizer pulley, a precision load-positioning device comprising an equalizer pulley support movably mounted upon said supporting structure for travel relatively thereto and having said equalizer pulley rotatably mounted thereon, and power-driven mechanism including a screw shaft operatively engaging said support and a threaded nut threadedly engaging said screw shaft for moving said support and said equalizer pulley relatively to said supporting structure toward and away from said load-holding block.

5. In a crane including a supporting structure carrying a rotatable cable winding drum and a rotatable equalizer pulley together with a hoisting cable trained around said drum and around the pulleys of a load-holding block suspended therefrom and also around said equalizer pulley, a precision load-positioning device comprising an equalizer pulley support movably mounted upon said supporting structure for travel relatively thereto and having said equalizer pulley rotatably mounted thereon, powerdriven mechanism including a screw shaft operatively engaging said support and a threaded nut threadedly engaging said screw shaft for moving said support and said equalizer pulley relatively to said supporting structure toward and away from said load-holding block, and an adjusting motor drivingly and rotatingly connected to said nut.

6. In a crane including a supporting structure carrying a rotatable cable Winding drum and a rotatable equalizer pulley together with a hoisting cable trained around said drum and around the pulleys of a load-holding block suspended therefrom and also around said equalizer pulley, a precision load-positioning device comprising an equalizer pulley support movably mounted upon said supporting structure for travel relatively thereto and having said equalizer pulley rotatably mounted thereon, and power-driven mechanism including a pair of screw shafts mounted on opposite sides of said support and operatively engaging said support and a threaded nut threadedly engaging each screw shaft for moving said support and said equalizer pulley relatively to said supporting structure toward and away from said load-holding block.

7. In a crane including a supporting structure carrying a rotatable cable winding drum and a rotatable equalizer pulley together with a hoisting cable trained around said drum and around the pulleys of a load-holding block suspended therefrom and also around said equalizer pulley, a precision load-positioning device comprising an equalizer pulley support movably mounted upon said supporting structure for travel relatively thereto and having said equalizer pulley rotatably mounted thereon, power-driven mechanism including a pair of screw shafts mounted on opposite sides of said support and operatively engaging said support and a threaded nut threadedly engaging each screw shaft for moving said support and said equalizer pulley relatively to said supporting structure toward and away from said load-holding block, and an adjusting motor drivingly and rotatingly connected to said nuts.

8. In a crane including a supporting structure carrying a rotatable cable winding drum and a rotatable equalizer pulley together with a hoisting cable trained around said drum and around the pulleys of a load-holding block suspended therefrom and also around said equalizer pulley, a precision load-positioning device comprising an equalizer pulley support movably mounted upon said supporting structure for travel relatively thereto and having said equalizer pulley rotatably mounted thereon, a screw shaft operatively engaging said support for moving said support and said equalizer pulley relatively to said supporting structure toward and away from said load-holding block, a nut threadedly engaging said screw shaft, gearing operatively and rotatingly engaging said nut, and an adjusting motor drivingly connected to said gearing.

References Cited in the file of this patent UNITED STATES PATENTS 496,427 Morgan May 2, 1893 718,160 Rundle Jan. 13, 1903 1,327,181 Taussig Jan. 6, 1920 2,343,640 Brown Mar. 7, 1944 

